/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.parsing;

import java.util.ArrayList;
import java.util.List;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * {@link ComponentDefinition} implementation that holds one or more nested
 * {@link ComponentDefinition} instances, aggregating them into a named group
 * of components.
 *
 * @author Juergen Hoeller
 * @see #getNestedComponents()
 * @since 2.0.1
 */
public class CompositeComponentDefinition extends AbstractComponentDefinition {

    private final String name;

    @Nullable
    private final Object source;

    private final List<ComponentDefinition> nestedComponents = new ArrayList<>();


    /**
     * Create a new CompositeComponentDefinition.
     *
     * @param name   the name of the composite component
     * @param source the source element that defines the root of the composite component
     */
    public CompositeComponentDefinition(String name, @Nullable Object source) {
        Assert.notNull(name, "Name must not be null");
        this.name = name;
        this.source = source;
    }


    @Override
    public String getName() {
        return this.name;
    }

    @Override
    @Nullable
    public Object getSource() {
        return this.source;
    }


    /**
     * Add the given component as nested element of this composite component.
     *
     * @param component the nested component to add
     */
    public void addNestedComponent(ComponentDefinition component) {
        Assert.notNull(component, "ComponentDefinition must not be null");
        this.nestedComponents.add(component);
    }

    /**
     * Return the nested components that this composite component holds.
     *
     * @return the array of nested components, or an empty array if none
     */
    public ComponentDefinition[] getNestedComponents() {
        return this.nestedComponents.toArray(new ComponentDefinition[0]);
    }

}
